Prometheus：Prometheus开发中间件Exporter

Prometheus 为开发这提供了客户端工具，用于为自己的中间件开发Exporter，对接Prometheus 。

目前支持的客户端

以go为例开发自己的Exporter

2.1依赖包的引入

工程结构

[root@node1 data]# tree exporter/
exporter/
├── collector
│   └── node.go
├── go.mod
└── main.go

1 directory, 3 files

引入依赖包

require (
    github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
    github.com/modern-go/reflect2 v1.0.1 // indirect
    github.com/prometheus/client_golang v1.1.0
        //借助gopsutil 采集主机指标
    github.com/shirou/gopsutil v0.0.0-20190731134726-d80c43f9c984
)

main.go

package main

import (
    "cloud.io/exporter/collector"
    "fmt"
    "github.com/prometheus/client_golang/prometheus"
    "github.com/prometheus/client_golang/prometheus/promhttp"
    "net/http"
)

func init()  {
     //注册自身采集器
    prometheus.MustRegister(collector.NewNodeCollector())
}
func main() {
    http.Handle("/metrics", promhttp.Handler())
    if err := http.ListenAndServe(":8080", nil); err != nil {
        fmt.Printf("Error occur when start server %v", err)
    }
}

为了能看清结果我将默认采集器注释,位置registry.go

func init() {
    //MustRegister(NewProcessCollector(ProcessCollectorOpts{}))
    //MustRegister(NewGoCollector())
}

/collector/node.go

代码中涵盖了Counter、Gauge、Histogram、Summary四种情况，一起混合使用的情况，具体的说明见一下代码中。

package collector

import (
    "github.com/prometheus/client_golang/prometheus"
    "github.com/shirou/gopsutil/host"
    "github.com/shirou/gopsutil/mem"
    "runtime"
    "sync"
)

var reqCount int32
var hostname string
type NodeCollector struct {
    requestDesc    *prometheus.Desc   //Counter
    nodeMetrics     nodeStatsMetrics  //混合方式 
    goroutinesDesc *prometheus.Desc   //Gauge
    threadsDesc    *prometheus.Desc  //Gauge
    summaryDesc    *prometheus.Desc  //summary
    histogramDesc  *prometheus.Desc   //histogram
    mutex          sync.Mutex
}
//混合方式数据结构
type nodeStatsMetrics []struct {
    desc    *prometheus.Desc
    eval    func(*mem.VirtualMemoryStat) float64
    valType prometheus.ValueType
}

//初始化采集器
func NewNodeCollector() prometheus.Collector {
    host,_:= host.Info()
    hostname = host.Hostname
    return &NodeCollector{
        requestDesc: prometheus.NewDesc(
            "total_request_count",
            "请求数",
            []string{"DYNAMIC_HOST_NAME"}, //动态标签名称
            prometheus.Labels{"STATIC_LABEL1":"静态值可以放在这里","HOST_NAME":hostname}),
        nodeMetrics: nodeStatsMetrics{
            {
                desc: prometheus.NewDesc(
                    "total_mem",
                    "内存总量",
                    nil, nil),
                valType: prometheus.GaugeValue,
                eval: func(ms *mem.VirtualMemoryStat) float64 { return float64(ms.Total) / 1e9 },
            },
            {
                desc: prometheus.NewDesc(
                    "free_mem",
                    "内存空闲",
                    nil, nil),
                valType: prometheus.GaugeValue,
                eval: func(ms *mem.VirtualMemoryStat) float64 { return float64(ms.Free) / 1e9 },
            },

        },
        goroutinesDesc:prometheus.NewDesc(
            "goroutines_num",
            "协程数.",
            nil, nil),
        threadsDesc: prometheus.NewDesc(
            "threads_num",
            "线程数",
            nil, nil),
        summaryDesc: prometheus.NewDesc(
            "summary_http_request_duration_seconds",
            "summary类型",
            []string{"code", "method"},
            prometheus.Labels{"owner": "example"},
        ),
        histogramDesc: prometheus.NewDesc(
            "histogram_http_request_duration_seconds",
            "histogram类型",
            []string{"code", "method"},
            prometheus.Labels{"owner": "example"},
        ),
    }
}

// Describe returns all descriptions of the collector.
//实现采集器Describe接口
func (n *NodeCollector) Describe(ch chan<- *prometheus.Desc) {
    ch <- n.requestDesc
    for _, metric := range n.nodeMetrics {
        ch <- metric.desc
    }
    ch <- n.goroutinesDesc
    ch <- n.threadsDesc
    ch <- n.summaryDesc
    ch <- n.histogramDesc
}
// Collect returns the current state of all metrics of the collector.
//实现采集器Collect接口,真正采集动作
func (n *NodeCollector) Collect(ch chan<- prometheus.Metric) {
    n.mutex.Lock()
    ch <- prometheus.MustNewConstMetric(n.requestDesc,prometheus.CounterValue,0,hostname)
    vm, _ := mem.VirtualMemory()
    for _, metric := range n.nodeMetrics {
        ch <- prometheus.MustNewConstMetric(metric.desc, metric.valType, metric.eval(vm))
    }

    ch <- prometheus.MustNewConstMetric(n.goroutinesDesc, prometheus.GaugeValue, float64(runtime.NumGoroutine()))

    num, _ := runtime.ThreadCreateProfile(nil)
    ch <- prometheus.MustNewConstMetric(n.threadsDesc, prometheus.GaugeValue, float64(num))

    //模拟数据
    ch <- prometheus.MustNewConstSummary(
        n.summaryDesc,
        4711, 403.34,
        map[float64]float64{0.5: 42.3, 0.9: 323.3},
        "200", "get",
    )

    //模拟数据
    ch <- prometheus.MustNewConstHistogram(
            n.histogramDesc,
            4711, 403.34,
            map[float64]uint64{25: 121, 50: 2403, 100: 3221, 200: 4233},
            "200", "get",
        )
    n.mutex.Unlock()
}